Information-based taste maps in insular cortex are shaped by stimulus concentration

Abstract

Taste processing is an essential ability in all animals signaling potential harm or benefit of ingestive behavior. Although the peripheral taste coding is well understood, current evidence for central taste processing remains contradictory. To address this issue, human participants judged pleasantness and intensity of low and high-concentration tastes (salty, sweet, sour, bitter) in two fMRI-experiments. High-resolution fMRI and multivariate pattern analysis were used to characterize taste-related informational content in human gustatory cortex (GC). Clusters within GC were narrowly tuned to specific tastants consistently across tasks. Importantly, taste concentrations completely altered the spatial layout of putative taste-specific maps with distinct, non-overlapping patterns for each taste category at different concentration levels. Together, our results point at population-level representations in human GC as a complex function of taste category and concentration.